The formula for determining the number of concurrently running tasks per node
is:
min (yarn.nodemanager.resource.memory-mb / mapreduce.[map|reduce].memory.mb,
yarn.nodemanager.resource.cpu-vcores / mapreduce.[map|reduce].cpu.vcores) .
For you scenario :
As you told yarn.nodemanager.resource.memory-mb is configured to 16 GB and
yarn.nodemanager.resource.cpu-vcores configured to 40. and I am thinking
mapreduce.map/reduce.memory.mb, mapreduce.map/reduce.cpu.vcores default values.
min (16GB/1GB,40Core/1Core )=16 tasks for Node. Then total should be 16*4=64
(63+1AM)..
I am thinking, Two Nodemanger's are unhealthy (OR) you might have configured
mapreduce.map/reduce.memory.mb=2GB(or 5 core).
As laxman pointed you can post RMUI or you can cross check like above.
Hope this helps.
Thanks & Regards
Brahma Reddy Battula
________________________________
From: Laxman Ch [[email protected]]
Sent: Friday, November 06, 2015 6:31 PM
To: [email protected]
Subject: Re: Max Parallel task executors
Can you please copy paste the cluster metrics from RM dashboard.
Its under http://rmhost:port/cluster/cluster
In this page, check under Memory Total vs Memory Used and VCores Total vs
VCores Used
On 6 November 2015 at 18:21, sandeep das
<[email protected]<mailto:[email protected]>> wrote:
HI Laxman,
Thanks for your response. I had already configured a very high value for
yarn.nodemanager.resource.cpu-vcores e.g. 40 but still its not increasing more
number of parallel tasks to execute but if this value is reduced then it runs
less number of parallel tasks.
As of now yarn.nodemanager.resource.memory-mb is configured to 16 GB and
yarn.nodemanager.resource.cpu-vcores configured to 40.
Still its not spawning more tasks than 31.
Let me know if more information is required to debug it. I believe there is
upper limit after which yarn stops spawning tasks. I may be wrong here.
Regards,
Sandeep
On Fri, Nov 6, 2015 at 6:15 PM, Laxman Ch
<[email protected]<mailto:[email protected]>> wrote:
Hi Sandeep,
Please configure the following items to the cores and memory per node you
wanted to allocate for Yarn containers.
Their defaults are 8 cores and 8GB. So that's the reason you were stuck at 31
(4nodes * 8cores - 1 AppMaster)
http://hadoop.apache.org/docs/r2.6.0/hadoop-yarn/hadoop-yarn-common/yarn-default.xml
yarn.nodemanager.resource.cpu-vcores
yarn.nodemanager.resource.memory-mb
On 6 November 2015 at 17:59, sandeep das
<[email protected]<mailto:[email protected]>> wrote:
May be to naive to ask but How do I check that?
Sometimes there are almost 200 map tasks pending to run but at a time only 31
runs.
On Fri, Nov 6, 2015 at 5:57 PM, Chris Mawata
<[email protected]<mailto:[email protected]>> wrote:
Also check that you have more than 31 blocks to process.
On Nov 6, 2015 6:54 AM, "sandeep das"
<[email protected]<mailto:[email protected]>> wrote:
Hi Varun,
I tried to increase this parameter but it did not increase number of parallel
tasks but if It is decreased then YARN reduces number of parallel tasks. I'm
bit puzzled why its not increasing more than 31 tasks even after its value is
increased.
Is there any other configuration as well which controls on how many maximum
tasks can execute in parallel?
Regards,
Sandeep
On Tue, Nov 3, 2015 at 7:29 PM, Varun Vasudev
<[email protected]<mailto:[email protected]>> wrote:
The number of parallel tasks that are run depends on the amount of memory and
vcores on your machines and the amount of memory and vcores required by your
mappers and reducers. The amount of memory can be set via
yarn.nodemanager.resource.memory-mb(the default is 8G). The amount of vcores
can be set via yarn.nodemanager.resource.cpu-vcores(the default is 8 vcores).
-Varun
From: sandeep das <[email protected]<mailto:[email protected]>>
Reply-To: <[email protected]<mailto:[email protected]>>
Date: Monday, November 2, 2015 at 3:56 PM
To: <[email protected]<mailto:[email protected]>>
Subject: Max Parallel task executors
Hi Team,
I've a cloudera cluster of 4 nodes. Whenever i submit a job my only 31 parallel
tasks are executed whereas my machines have more CPU available but still
YARN/AM does not create more task.
Is there any configuration which I can change to start more MAP/REDUCER task in
parallel?
Each machine in my cluster has 24 CPUs.
Regards,
Sandeep
--
Thanks,
Laxman
--
Thanks,
Laxman
